Removable outrigger assembly with rotatable jack

ABSTRACT

A removable extensible outrigger assembly of the type including opposite vertical jacks has one jack rotatable to a horizontal position so that the assembly can be removed sidewardly from beneath a carrying vehicle. In one embodiment, the extensible outrigger beam is split into two sections that are normally locked together; and there is a cylindrical cam connection between the extension cylinder and outer section so that extension of the cylinder when the sections are unlocked causes the outer section and jack to be extended and rotated 90*. A second embodiment is similar, but the outer section is held against extension during rotation. In a third embodiment the jack is rotated pivotally using a slotted lever connection.

United States Patent [1 1 Grider et a1.

[ Sept. 17, 1974 REMOVABLE OUTRIGGER ASSEMBLY WITH ROTATABLE JACK [75] Inventors: Lyle D. Grider, New Berlin, Wis.;

Robert J. Cleereman, Wooster, Ohio [73] Assignee: Bucyrus-Erie Company, South Milwaukee, Wis.

[22] Filed: July 9, 1973 [21] Appl. No.: 377,515

Crisp 212/145 Attorney, Agent, or Firm-Quarles & Brady [57] ABSTRACT A removable extensible outrigger assembly of the type including opposite vertical jacks has one jack rotatable to a horizontal position so that the assembly can be removed sidewardly from beneath a carrying vehicle. In one embodiment, the extensible outrigger beam is split into two sections that are normally locked together; and there is a cylindrical cam connection between the extension cylinder and outer section so that extension of the cylinder when the sections are unlocked causes the outer section and jack to be extended and rotated 90. A second embodiment is similar, but the outer section is held against extension during rotation. In a third embodiment the jack is rotated pivotally using a slotted lever connection.

6 Claims, 13 Drawing Figures PATENIED I 3.836.012

' sum 1 or 5 REMOVABLE OUTRIGGER ASSEMBLY WITH ROTATABLE JACK BACKGROUND OF THE INVENTION This invention relates particularly, but not only, to truck mounted cranes. Such machines have come into increasing use because of their ready transportability from site to site. In some cases, however, particularly for newer, very large machines, transportation presents a problem because the total working weight of the machines exceeds highway load limit restrictions. To overcome this problem, manufacturers have taken to making certain components of the machine removable so that they can be transported separately, thus reducing the travel weight of the machine. It is very common to provide removable counterweights for this purpose, but where this does not provide sufficient weight reduction other components also have to be removable. Outrigger assemblies are particularly suitable for this purpose, since they are relatively heavy but are separately mounted on the underside of the carrier so that they may easily be made removable.

Most machines of the contemplated type have two sets of Outriggers, one at the very rear of the machine and the other between the front and rear wheels of the carrier vehicle. Removal of the rear outrigger assembly presents no particular problem, since the jacks can be extended to support the weight of the assembly, whereupon it can be disconnected from the carrier and lowered to the ground by retracting the jacks. Thereafter, the carriable vehicle can be moved forward away from the outrigger assembly so that the crane boom can be used to lift the outrigger onto a separate carrying vehicle. Removal of front outrigger assemblies, however, presents a much more difficult problem since these are located between the front and rear wheels of the carrier vehicle; as a result, the vehicle cannot be driven away from the outrigger assembly and the assembly must instead by pulled sidewardly from beneath the vehicle. Removing the outrigger assembly sidewardly, however, is difficult because the vertical jacks are usually too high to clear the underside vehicle frame. Accordingly, it has heretofore been necessary either to remove one of the vertical jacks or to tip the entire outrigger assembly on its side so that it can be pulled out. Neither procedure is easy, particularly for large outrigger assemblies which may weigh or 6 thousand pounds.

SUMMARY OF THE INVENTION This invention contemplates a removable outrigger assembly in which at least one of the vertical jacks can be rotated to a horizontal position where it can clear the vehicle frame, rotation being accomplished by using the hydraulic cylinder or other linear actuator which otherwise serves to extend and retract the outrigger beam. This is accomplished by mounting at least one jack so that it is rotatable and providing lock means to hold it in its normal vertical position. A suitable motion converting connection is provided and is operatively interposable between the linear actuator for the outrigger beam and the jack so that extension of the actuator when the lock means is released causes the jack to be rotated to the desired horizontal position.

The invention is depicted in several embodiments, all of which are relatively simple and inexpensive, have substantial mechanical strength, and are relatively easy to manufacture, assemble, operate and maintain. Further objects and advantages will appear from the description to follow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view in elevation of a truck crane including a removable front outrigger assembly constituting a first preferred embodiment of the invention,

FIG. 2 is an enlarged fragmentary view in cross section through the plane 2-2 shown in FIG. 1,

FIG. 3 is a view in cross section through the plane 3-3 shown in FIG. 2,

FIG. 4 is a further enlarged fragmentary view in cross section, partially broken away, through the plane 4-4 shown in FIG. 3, but showing the outrigger assembly disconnected from the carrier vehicle,

FIG. 5 is a view in cross section through the plane 5-5 shown in FIG. 4,

FIG. 6 is a view in cross section, partially broken away, similar to FIG. 4 but showing the vertical jack in an extended and rotated position,

FIG. 7 is a view in cross section the plane 77 shown in FIG. 6,

FIG. 8 is a view similar to FIG. 4, but illustrating a second embodiment of the invention,

FIG. 9 is a view similar to FIG. 8 but showing the vertical jack in a rotated position,

FIG. 10 is a view in cross section through the plane 10-10 shown in FIG. 8,

FIG. 11 is a view similar to FIG. 4 but illustrating a third embodiment of the invention,

FIG. 12 is a view similar to FIG. 11, but showing the vertical jack in a rotated position, and

FIG. 13 is a view in cross section through the plane l3-13 shown in FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The truck crane shown in FIG. 1 is of generally con ventional construction and includes a carrier vehicle having a frame 1, front wheels 2 and rear wheels 3. As is conventional in such machines, the frame 1 is of box or I-beam construction and is relatively narrow so as to fit between the wheels and may be appropriately decked. A revolving frame 4 is supported on the frame 1 and mounts a telescopic boom 5. Since the construction of such machines is well known to those skilled in the art, and since the invention is applicable to various types of machines, the truck crane has been shown somewhat schematically and will not be described in detail. It should also be noted that the outrigger assembly to be described below has been shown somewhat schematically for the sake of clarity and simplicity. It will be understood by those skilled in the art that vari- 'ous components might be made in many different ways and that there will be additional or appurtenant elements such as hydraulic connections, bearing plates, etc., all well known, not shown in the drawings.

The truck crane shown in FIG. 1 includes two removable outrigger assemblies, a rear assembly 6 and a front assembly 7. The rear assembly 6 is not shown nor will it be described in detail; it is basically similar to the front assembly 7 but does not include means for rotating one jack or the wheels to be described below, these not being necessary for removal of a rear assembly for the reasons noted above.

The front outrigger assembly 7 includes a tubular housing 8 that is of basically square cross section and is disposed transversely to the length of the frame 1 between the front wheels 2 and rear wheels 3. The housing 8 is preferably made up of two U-shaped halves which have facing open ends welded or otherwise affixed to a central plate 9 so that the housing 8 defines two parallel, rectangular, beam receiving channels. The lowermost channel as seen in FIG. 3 telescopically receives an extensible and retractable outrigger beam 10 which is tubular and of generally rectangular cross section, and a conventional double acting vertical hydraulic jack 11. The beam 11 is extended and retracted by means of a conventional double acting hydraulic cylinder (not shown) which has one end pinned to the housing 8 and its other end pinned to the beam 10. The upper housing channel as seen in FIG. 3 telescopically receives an extensible and retractable beam 12 which is generally similar to the beam 10 except for the features to be noted below; and a second vertical double acting hydraulic jack 13 is mounted at the end of the beam 12. The ends of the housing channels opposite those through which the beams 10 and 12 extend are preferably closed off.

Two spaced pairs of apertured mounting brackets 14 are fixed to the top of the housing 8 and receive respective apertured ears 15 which are fixed to the sides of the frame 1. Removable pins 16 extend through the brackets 14 and ears 15 to removably mount the entire assembly 7 on the underside of the frame 1. A pair of U-shaped handle brackets 17 have their legs fixed to the sides of the housing 8 and extend above the housing to present loops 18 which can receive cable hooks for the purpose of lifting and moving the assembly 7 after it has been removed as will be described. A pair of U- shaped wheel mounting brackets 19 also have their legs fixed to the sides of the housing 8 and serve to mount two pair of wheels 20 which extend slightly below the housing 8 and allow it to be wheeled out from under the frame 1 after it has been removed this being a very important feature for heavy assemblies.

The jacks 11 and 13 extend substantially above the housing 8, and if the front outrigger assembly 7 is lowered to the ground it cannot be pulled out sidewardly from beneath the frame 1 because they will not clear the underside of the frame and/or elements that may extend downwardly from it. Therefore, and in accordance with the basic purpose of the invention, the jack 13 is made to be rotatable to a horizontal position in which it will clear the underside of the frame 1. In the embodiment shown, only the jack 13 has been made rotatable so that the assembly 7 can be pulled out only from the side on which the jack 11 is mounted; but it will be understood that the jack 1] could be made rotatable in the same manner to allow the assembly 7 to be removed from either side.

As can be seen clearly in FIG. 4, the beam 12 is split transversely of its longitudinal axis and near its outer end to define an inner section 21 and an outer section 22. Two pairs of opposite connecting plates 23 have their outer ends fixed to the inner side surfaces of the outer section 22 and extend inwardly to face the inner side surfaces of the inner section 21. Releasable lock means in the form of removable pins 24, seen clearly in FIG. 5, extend through apertures in the plates 23 and the side walls of the section 21 to normally lock the sections 21 and 22 together so that they extend and retract as a unit, with the jack 13 in its normal vertical position.

A conventional double acting hydraulic actuating cylinder 25 serves as a linear actuator for the beam 12 and has its cylinder end connected to the housing 8 by any suitable conventional means (not shown). The forward or rod end of the cylinder casing is supported within the hollow beam 12 by a spider 26 made up of four arms which extend radially to and ride on the side and upper and lower surfaces of the interior of the beam 12, the cylinder casing thus being held in the desired orientation while allowing the beam 12 to slide inwardly and outwardly. The extensible and retractable rod 27 of the cylinder 25 would in conventional assemblies simply be pinned to the beam 12; but in this assembly it is pinned to an elongated cylindrical cam member 28, the outer end of which is fixed to a vertical support plate 22' that extends across and is fixed to the interior walls of the outer beam section 22. The cam 28 extends through and is supported by a cylindrical sleeve 29 which is fixed to two vertical support plates 30 which are secured to the interior surfaces of and extend across the inner beam section 21 near its outer end. As can be seen clearly from FIGS. 4 and 6, the outer surface of the cam 28 is provided with two opposite, mirror cam slots 31. These are generally helical, but have relatively short straight section 31 at their outermost ends. Opposite cam follower pins 32 are fixed to the sleeve 29 and extend into the slots 31.

In FIGS. 2-5, the beam 12 is shown in its normal working state, with the inner and outer beam sections 21 and 22 releasably locked together by the pins 24 and the jack 13 vertical. In this condition, extension and retraction of the rod 27 will simply cause the entire beam 12 to be extended or retracted as a unit. When the beam 12 is suitably extended, the jack 13 can be extended vertically to assist in supporting the machine during working there will be a float (not shown) fixed to thte rod of the jack 13.

When it is desired to remove the outrigger assembly '7, the beams 10 and 12 are retracted and the jacks 11 and 13, with floats in place, are extended vertically to the point where they are touching the ground and supporting the weight of the assembly 7. Thereafter, the pins 16 are removed to disconnect the assembly 7 from the frame 1, and the jacks 11 and 13 are retracted to lower the assembly 7 to the point where the wheels 20 are on the ground. The jacks l1 and 13 are then fully retracted and the floats removed, the assembly then being as shown in FIGS. 4-7. Thereafter, the pins 24, which are beyond the housing 8 and thus exposed even when the beam 12 is fully retracted, are removed and the rod 27 on the cylinder 25 is extended. Since the outer section 22 is no longer locked to the inner section 21, such extension will cause only the section 22 to move outwardly. During the course of this movement, however, the motion converting connection afforded by the cylindrical cam 28 and followers 32 will cause the outer section 22, and thus the jack 13, to be rotated through to the horizontal position shown in FIGS. 6 and 7. The short straight section 31 of the cam slots 31 insure that the section 22 will be moved outwardly far enough for the plates 23 to clear the inner section 21 before there is any rotation. Once the jack 13 is in horizontal position, it will clear the underside of the frame 1 so that the entire assembly 7 can be pulled out from the opposite side. Again, the wheels make this possible even where the assembly 7 is very heavy.

Once the assembly 7 has been pulled out from under the frame 1, the boom 5 can be used to lift the entire assembly 7 to another carrier vehicle. If desired, the jack 13 can be rotated back to vertical position and retracted for transportation, or it can be left in its horizontal position for reattachment at the next site. Reattachment is accomplished simply by keeping or shifting the jack 13 to the position shown in FIG. 6 and rolling the assembly 7 back under the frame 1. Once the assembly 7 is in proper position, the jack 13 is rotated back to vertical position and retracted, by retracting the rod 27, and the pins 24 are reinserted. Floats are attached to the jacks 11 and 13, and they are then extended to raise the assembly 7 to a position where the pins 16 can be reinserted, after which the assembly 7 is ready for working.

In some cases it may be desirable to provide for rotation of a vertical jack to a horizontal position without axial extension, and FIGS. 8-10 show a second embodiment of the invention which accomplishes this. This embodiment is very similar in many respects to the embodiment of FIGS. 1-7, and the same reference numerals have been used for substantially identical parts. The embodiment of FIGS. 8-10 includes an extensible and retractable beam 33 which is split transversely of its longitudinal axis near its outer end to define an inner section 34, and an outer section which supports the jack 13. The facing portions of the sections 34 and 35 are shaped to define facing annular flanges 34 and 35'. The flanges 34 and 35 are each provided with three equally circumferentially spaced apertures 36 which are aligned and removably receive pins 37 which serve as releasable locks that normally hold the sections 34 and 35 together as a unit with the jack 13 upright. The outer flange 35 is also provided with three equally circumferentially spaced, .I-shaped retainers 38 which are bolted to the flange 35 and hook over the flange 34' to hold the sections 34 and 35 against relative axial movement while allowing relative rotational movement.

The rod 27 in the embodiment of FIGS. 8-10 is pinned to a tubular slide member 39 which is slidably supported by a sleeve 40 which is in turn supported by two vertical support plates 41 which are fixed to the inner surfaces of the inner beam section 34. The outer surface of the slide 39 is provided with a straight keyway 42 which receives a key pin 43 that extends through the sleeve 40, these elements providing a keyed connection that allows the slide 39 to move axially with respect to the sleeve 40 but prevents relative rotational movement.

Telescopically received within the outer end of the slide 39 is a cylindrical cam member 44 which has its outer end fixed to a support plate 45 that extends across and is fixed to the inner suffaces of the outer beam section 35. The external surface of the cam 44 is provided with a single helical cam slot 46 which receives a cam follower pin 47 fixed to the slide 39.

When the pins 37 are in place as shown in FIG. 8, the entire beam 33 will extend and retract as a unit in reposne to extension or retraction of the rod 27. For removal, the entire assembly is removed from the underside of the frame 1 and lowered to the ground in the same manner as the embodiment of FIGS. 1-7. Thereupon, the pins 37 are removed and the rod 27 is again extended. Because of the motion converting connection afforded by the cam 44 and follower pin 47, such extension will cause the entire outer section 35, with the jack 13, to rotate the horizontal position shown in FIG. 9, the retainers 38 preventing relative axial movement of the section 35 with respect to the section 34. Once the jack 13 is in the horizontal position shown in FIG. 9, the assembly can be rolled out from under the frame 1 and transferred to another vehicle as with the first embodiment.

In both the first and second embodiments, the inner beam sections, 21 or 34, are heavy enough so that they will remain in place when the rod 27 is extended to rotate the outer section 22 or 35. If desired, however, removable pins or other means could be provided to lock the inner section 21 or 34 in retracted position in the housing 8 during rotation of the jack 13.

The embodiment of FIGS. 11-13 operates on a slightly different principle in that motion converting connection in the form of a slotted lever is used to rotate the jack 13 and it is rotated in pivotal fashion rather than about the longitudinal axis of the beam. Again, the same identical to those in the prior embodiments.

The embodiment of FIGS. 11-13 includes a beam 48 that is split transversely of its longitudinal axis to define an inner section 9 and a very short outer section 50 which mounts the jack 13. An apertured hinge member 51 on the upper surface of the outer end of the inner section 49 mates with an apertured hinge member 52 on the outer section 50, and a hinge pin 53 completes a hinge connection between the beam sections 49 and 50. An apertured ear 54 is provided on the lower surface of the inner section 49 near its outer end, and this mates with an apertured ear 55 on the outer section 50. A removable pin 56 extends through the ears 54 and 55 to serve as a releasable lock that normally holds the sections 49 and 50 together so that the beam 48 extends and retracts as a unit with the jack 13 upright.

The cyinder rod 27 is normally connected by a removable pin 57 to a bifurcated bracket 49 attached to the inner section 49 so that it can effect extension and retraction of the beam 48. A bifurcated slotted lever 58 has its outer end fixed to the outer beam section 50 and extends inwardly into the interior of the inner section 49. The inner beam section 49 is provided with opposite access openings 59 near the inner end of the lever 58.

The assembly of FIGS. 11-13 is removed by disconnecting it from the frame 1 and lowering it to the ground in the manner of the previous embodiments. Thereafter, the pin 57 is removed and the rod 27 is extended to bring it to the inner end of the lever 58. The pin 57 is then used to connect the rod 27 to the lever 58 through the slots therein. The access openings 59 allow the pin 57 to be easily removed and reconnected. The pin 56 is then removed to unlock the outer section 50, and the rod 27 is extended. During the first phase of this movement, the pin 57 will simply move from the left to the right ends of the slots in the lever 58 as seen in FIG. 11. Thereafter, however, further extension of the rod 27 will cause the outer section 50 and jack 13 to pivot upwardly or counterclockwise to the position shown in FIG. 12, the slot in the lever 58 serving to accommodate the pivotal movement. When the jack 13 is in the position shown in FIG. 12, its vertical height has been substantially reduced and, again, the entire assembly may then be rolled out from under the frame 1. When the assembly is reattached, the foregoing process is reversed. This embodiment differs from the first two in that the motion converting connection afforded by the lever 58 and pin 57 is an alternative connection, but the required connections are quite simple.

All three embodiments provide for simple rotation of the vertical jack to a horizontal position to reduce its overall height so that the outrigger assembly can easily be pulled or rolled from under the vehicle frame 1. While these are preferred embodiments which accomplish the objectives of the invention, it will be apparent that changes and modifications might be made without departure from the spirit of the invention. The invention is, for example, applicable to outrigger assemblies using linear actuators other than double acting hydraulic cylinders, and various cam or other motion converting connections could be used to accomplish the desired rotation. The invention is applicable to outrigger assemblies with multiple telescoped extensible beams. As a result, the invention is not intended to be limited by the showing or description herein, or in any other manner, except insofar as may specifically be required.

We claim:

1. In a removable outrigger assembly of the type including a housing releasably mounted on the underside of a vehicle frame, vertical jacks at opposite ends of the housing, at least one of which is mounted at the end of a beam received in and extensible and retractable with respect to the housing, and a linear actuator for extending and retracting the beam,

the improvement wherein:

said one jack is rotatable with respect to the beam be:

tween its vertical position and a horizontal position; there is a releasable lock means to hold said one jack in its vertical position, the actuator serving when the lock means is operative to extend and retract the beam and said one jack as a unit with the jack remaining in its vertical position substantially throughout the range of travel of the beam; and there is a motion converting connection operatively interposable between said one jack and the actuator to cause said one jack to rotate to and from its horizontal position in response to operation to the actuator only when the lock means is released.

2. A removable outrigger assembly according to claim 1, wherein: the actuator is a double acting hydraulic cylinder; and the beam on which said one jack is mounted is split transversely of its longitudinal axis to define an inner portion and an outer portion, with said one jack being mounted on said outer portion; and

there is a releasable lock means that normally holds the inner and outer beam portions together to extend and retract as a unit with said one jack in vertical position; and the motion converting connection comprises a cylindrical cam means connected between the cylinder and the outer beam section to cause rotation of the outer section and said one jack about an axis parallel to the longitudinal axis of the beam only when the cylinder is extended or retracted while the lock means is released.

3. The arrangement of claim 2 wherein: the one end of the cylinder is fixed to the inner end of a cylindrical cam member which has-its outer end fixed to the outer beam section; and there is a sleeve mounted on the inner beam section through which the cylindrical cam rotatably extends; and the exterior of the cylindrical cam is provided with a helical cam slot which receives a cam follower fixed to the sleeve.

4. The arrangement of claim 2, wherein: one end of the cylinder is fixed to a tubular slide member which is supported by the inner beam section to be capable of relative axial movement but be held against relative rotational movement with respect thereto; and there is a cylindrical cam member that has its outer end fixed to the outer beam section and its inner end received in the slide; and the exterior surface of the cam member is provided with a helical cam slot which receives a cam follower fixed to the slide.

5. The arrangement of claim 1 wherein: the actuator comprises a double acting hydraulic cylinder that has one end connected to the housing and its other end releasably connected to the beam; and the beam is split transversely of its longitudinal axis to define an inner section and an outer section, with said one jack being mounted on the outer section; and the outer section of the beam is hinged to the inner section to be pivotal about an axis transverse to the longitudinal axis of the beam; and there is a releasable lock means to hold the outer beam section in line with the inner beam section and prevent pivotal movement; and the motion converting connection comprises a slotted lever extending inwardly from the outer beam section that is adapted to be connected to the said other end of the cylinder.

6. The arrangement of claim 1 wherein: the housing is provided with wheels which are above the ground when the outrigger assembly is mounted on the vehicle frame and which extend below the housing to allow the assembly to be rolled in a direction parallel to its longitudinal axis when the assembly has been disconnected from the vehicle frame.

" CERTIFICATE OF CORRECTION Patent No. 3,836, 012' I Dated September 1974 Inventofl) Lyle D. Grider and Robert J. Cleerem an It is certified that error appears in the and that said Letters Patent are hereby corrected as'shown below:

C olumn 1,

I Column 1, Column 2,

Column 3,

Column 4,

Column 4,

Column 5, Column 5,

' Column 6,

Column 6 Column- 6 Column 6 Colurnn 7 UNITED STATES PATENT oFF ICE line- 57 line 4,

line "23, 1

fine 27,

line 40,

' A Signed and sealed this 7th dayl'qf January 1975 (SEAL) Atte'st:

-- of the should appear after "uhder 'sidefi "section" should read sections ales,"

' to should appear after-"rotate" I "oyinder" should read -'-"cy linder "to" should read of above-identified patent y" should read be ,r

-- through should appear after "section" "beam 11" should read beam-10 I "thte" should read the "suffaces" Should read -{surfaces "repos'ne" should read -j-r'esponse after "same" the following-should appear: reference numerals have been used to refer to parts that are substantially "section 9"v should read n-"section 49 c.;r1ARssALL DANN Y Commissioner of Patents- 

1. In a removable outrigger assembly of the type including a housing releasably mounted on the underside of a vehicle frame, vertical jacks at opposite ends of the housing, at least one of which is mounted at the end of a beam received in and extensible and retractable with respect to the housing, and a linear actuator for extending and retracting the beam, the improvement wherein: said one jack is rotatable with respect to the beam between its vertical position and a horizontal position; there is a releasable lock means to hold said one jack in its vertical position, the actuator serving when the lock means is operative to extend and retract the beam and said one jack as a unit with the jack remaining in its vertical position substantially throughout the range of travel of the beam; and there is a motion converting connection operatively interposAble between said one jack and the actuator to cause said one jack to rotate to and from its horizontal position in response to operation to the actuator only when the lock means is released.
 2. A removable outrigger assembly according to claim 1, wherein: the actuator is a double acting hydraulic cylinder; and the beam on which said one jack is mounted is split transversely of its longitudinal axis to define an inner portion and an outer portion, with said one jack being mounted on said outer portion; and there is a releasable lock means that normally holds the inner and outer beam portions together to extend and retract as a unit with said one jack in vertical position; and the motion converting connection comprises a cylindrical cam means connected between the cylinder and the outer beam section to cause rotation of the outer section and said one jack about an axis parallel to the longitudinal axis of the beam only when the cylinder is extended or retracted while the lock means is released.
 3. The arrangement of claim 2 wherein: the one end of the cylinder is fixed to the inner end of a cylindrical cam member which has its outer end fixed to the outer beam section; and there is a sleeve mounted on the inner beam section through which the cylindrical cam rotatably extends; and the exterior of the cylindrical cam is provided with a helical cam slot which receives a cam follower fixed to the sleeve.
 4. The arrangement of claim 2, wherein: one end of the cylinder is fixed to a tubular slide member which is supported by the inner beam section to be capable of relative axial movement but be held against relative rotational movement with respect thereto; and there is a cylindrical cam member that has its outer end fixed to the outer beam section and its inner end received in the slide; and the exterior surface of the cam member is provided with a helical cam slot which receives a cam follower fixed to the slide.
 5. The arrangement of claim 1 wherein: the actuator comprises a double acting hydraulic cylinder that has one end connected to the housing and its other end releasably connected to the beam; and the beam is split transversely of its longitudinal axis to define an inner section and an outer section, with said one jack being mounted on the outer section; and the outer section of the beam is hinged to the inner section to be pivotal about an axis transverse to the longitudinal axis of the beam; and there is a releasable lock means to hold the outer beam section in line with the inner beam section and prevent pivotal movement; and the motion converting connection comprises a slotted lever extending inwardly from the outer beam section that is adapted to be connected to the said other end of the cylinder.
 6. The arrangement of claim 1 wherein: the housing is provided with wheels which are above the ground when the outrigger assembly is mounted on the vehicle frame and which extend below the housing to allow the assembly to be rolled in a direction parallel to its longitudinal axis when the assembly has been disconnected from the vehicle frame. 